<html>
  <head>
    <title>audio</title>
    <style>
      #rtc {
        width: 160px;
        height: 90px;
      }
    </style>
  </head>
  <body>
    <video id="rtc" autoplay>animation</video>
  </body>
  <script>
    navigator.mediaDevices
      .getUserMedia({
        audio: false, // We want an audio track
        video: true, // ...and we want a video track
      })
      .then(localStream => {
        document.getElementById('rtc').srcObject = localStream
      })
      .catch(err => {
        console.log(err)
      })
  </script>
</html>
